1. Field of the Invention
The present invention relates to allergen testing. More specifically, it relates to a device for allergen testing that includes a pair of sensing electrodes, an allergen delivery electrode connected to an allergen sample tray, a microprocessor for amplifying and comparing the signals from the two sensing electrodes, an A/D converter for turning the amplified data to a digital information stream, and an interface including software to display and store the gathered information on a conventional personal computer (PC).
2. Description of the Prior Art
Presently, allergy testing commonly takes the form of introducing allergens to a portion of the patients' dermis and then measuring the size and color of the induced weal. This often involves breaking the surface of the skin to introduce the substance and has a number of drawbacks. It is painful, for one, and the patient can have a severe reaction if they are extremely sensitive to one of the introduced substances. Additionally, the procedure causes some discomfort. Another prior art method of testing involves introducing the potential allergen and then measuring the temperature response, by means of electrodes or the other sensing means, of the skin proximate the area where the substance was introduced. This allows for smaller amounts of the allergen to be used, but in many cases it still involves the breaking of the skin. The present invention attempts to improve on these prior art methods and devices by using galvanometric skin response to determine the sensitivity of the patient to various substances. As will be seen, the simplicity and effectiveness of my invention is not rivaled in the prior art.
There have been a number of U.S. Patents issued that relate to this art that were uncovered during a search, and they are hereinafter discussed:
U.S. Pat. No. 4,702,259, issued on Oct. 27, 1987 to Marc Ferreira et al., discloses a device for measuring and indicating changes in the electrical resistance of a living body. The device includes an analog portion, a digital portion and a stable source of power for both portions. The analog portion includes a bridge network which includes a potentiometer, which turns together with the potentiometer provided in the digital portion, and digital processing circuitry. Digital displays determine and display a count indicative of the position of the potentiometer and the total amount of rotation of said potentiometer. In addition, a computer may be interfaced with the device to record or play back the changes in the resistance of the living body. Unlike the present invention, there is nowhere in the document a teaching or disclosure that discusses using the apparatus as a testing device for allergen response, nor is there any type of delivery system for stimuli disclosed.
U.S. Pat. No. 4,805,621 issued to Roland Heinze et al. on Feb. 21, 1989 discloses an apparatus for measuring the impedance of body tissue with a signal source connected to the tissue to be measured which supplies an electrical signal to the tissue, a unit for acquiring an impedance signal from the body tissue dependent on the electrical signal, and a evaluation stage for the impedance signal. The evaluation stage filters out low frequency signal components corresponding to the conductance of the tissue, and has a signal output to which the signal components which were filtered out are supplied. In this device, an electrical signal is impressed on the tissue of the patient through a pair of electrodes and the voltage drop is measured. This is unlike the present invention, which measures the galvanometric skin response in the presence of allergenic substances and displays the same.
Next in this discussion is U.S. Pat. No. 4,809,707 issued to Thomas L. Kraft et al. on Mar. 7, 1989. Kraft et al. show an electrode for performing a plurality of allergy tests on a patient undergoing tests. The allergy electrode consists of a plurality of individual testing electrodes and a single common electrode. Each of the testing electrodes includes allergen delivery apparatus and a temperature sensor. The allergen is contained in a removable allergen impregnated pad. If a dry allergen is used, it may be hydrolized with a drop of distilled water prior to application. A small electric charge charges a charge plate on one side of the allergen pad and a common ring on the electrodes is grounded in a circuit with the charging plate, thereby causing electric field to transfer the allergen through the pores of the skin. The area surrounding the allergen delivery area is sensed for temperature by a thin film temperature sensor and a rigid temperature conducted base. A thermistor or other temperature to voltage transducer converts the sensed temperature to an electric voltage which is applied through appropriate differential amplifiers and multiplexer to an analog to digital converter. The digital data is then stored by a microprocessor in random access memory. An output device can be connected to receive the stored data and the time at which it was stored so as to manifest to the physician the change in temperature of the tested area with respect to time. This discloses an electrode for non-invasive allergy testing. Included are plurality of testing electrodes and a common electrode. Each of the testing electrodes have therein an allergen impregnated pad, a charge plate, a common ring grounded in the circuit with the charge plate, and a thin film temperature sensor or the like. A small charge is placed on the charge plate, which causes the allergen to transfer through the pores of the skin, while the thin film sensors monitor temperature in the proximate area. The common electrode monitors the temperature in a distant area. Processing and storage means are disclosed to allow the physician to review the results of the test.
Lastly, U.S. Pat. No. 4,819,657 issued on Apr. 11, 1989, also to Thomas L. Kraft et al. discloses a automatic allergy detection system. The system includes an electrode capable of testing up to eight different allergies and an associated electronic unit. The electrode includes apparatus to transcutaneously deliver an allergen to the patient without puncturing the patient's skin. The electrode also includes a temperature sensor for sensing the skin temperature in the area surrounding the deliver of the allergen. Electronic apparatus is provided for processing the sensed temperature and storing data related thereto for subsequent print out to an output device. The allergy testing system is controlled so that periodic temperature readings are made at thirty second intervals over approximately a fifteen minute testing span. The data can be printed out in a graphic format to allow the physician to easily and quickly make more accurate diagnosis. In this device there are disclosed electrodes similar to those discussed in Kraft et al. ('707). However, more detail is gone into concerning the processing and data storage portion of the device. Neither of the two Kraft et al. patents discusses the use of galvanometric skin response as a method of ascertaining a patients sensitivity to a specific substance.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.